The Alien Blaster within Fallout 3 is one the post powerful weapons in the game. Due to its 100% critical rate, almost all enemies can be dispatched in 1 shot. This is true, even when the weapon is in poor condition.

With the Broken Steel expansion, another one can be found inside Adams Air Force Base. It is within the armory, in a locked box (Hard difficulty) inside the Mobile Base Crawler. There are also Alien Power Cells inside the numerous ammunition boxes.